Thursday, July 29, 2004

In the past I had come across the idea that the universe could perhaps be described by a theory which used information as the foundational concept. However, at the time I didn’t think much of it. The idea connoted to me a computer-inspired model of the world, and I have thought that information processing or computational concepts wouldn’t add anything special beyond the approach provided by physics. After all, in order to describe a real-world system, a computational model needs to be implemented in a physical causal context, which means it reduces to physics. Further, a model based on traditional or classical information theory would seemingly not bring anything to the table that classical physics couldn’t – and we already know classical physics isn’t the whole story for the universe given the 20th century advent of quantum mechanics.

However, recently I realized that information could be a richer concept. Here’s the insight: the existence of information leads one to ask – information for whom? The traditional physical description of the world doesn’t ask this question. Physical object “A” impacts physical object “B” and so on. We do not include a subject of experience in the model. This is the reason traditional scientific approaches find it so hard to grapple with our own first-person consciousness.

In information theory, “A” transmits information which is received by “B”. We can interpret this in a way which captures the duality of the subjective and objective perspectives we encounter in our own experience. The information provided by A is the objective side of this exchange; B’s receipt of the information is a subjective experience. Now, if the objects in question are billiard balls, it seems superfluous to suggest that B has a subjective experience. But to eventually explain consciousness, we need to account for how experience might fit in even at rudimentary levels of reality.

Very speculatively, it may be that the extra richness inherent in such a model can help explain other mysteries faced by science. For instance in the subatomic world described by quantum physics, experimenters have shown that pairs of particles can be “entangled” with each other. This means that if we measure one of the particles in the pair to discover if it has a certain kind of spin or charge, the other particle will take on the matched characteristic, even though it is not in local contact with the first. Perhaps we could say that it was in receipt of information from its partner, however.

Maybe there is an application in the area of “complexity theory”. We observe complex systems that show emergent behavior at the macro-level that can’t be readily explained by the local physical behavior of the micro-level parts. Perhaps in these cases there is an information exchange which binds the system together.

My crude sketch of information flow (which includes an aspect which goes beyond normal physical causality) may be off-base. Hopefully experts will figure out whether it has merit. I continue to believe strongly that we will need to expand or richen our traditional scientific methodology in some way to fully account for all of the phenomena in the world, including consciousness.

Thursday, July 22, 2004

I’ve always been amazed by the amount of controversy regarding evolution. Evolution is probably the most important and powerful concept to come out of science and it is central to our increasing understanding of the natural world. But, frustrating as it is for defenders of science, it is a brute fact that a huge number of people feel evolution and other well-founded scientific theories are in opposition to their personal values and/or religious beliefs. What I want to do in this post is present an optimistic vision of how the cultural divide epitomized by the evolution wars might be reduced in the years to come. The solution lies in the expansion and richening of the scientific worldview.

Let me offer a crude sketch of the worldview typically associated with science in our culture today. The universe consists of bits of inanimate matter moving in a vacuum of space. Any large object or system can be understood by breaking it down into these small bits and analyzing their interaction. It all got started in a big bang (somehow), and since then has evolved in a mechanistic way. Human beings are part of the system and our lives are therefore also completely determined by mechanism.

To the extent that folks believe science is irrevocably committed to this worldview, it is understandable that there would be a big disconnect. It isn’t only a question of this worldview conflicting with specific religious beliefs. People of all backgrounds and beliefs intuitively sense that it is an incomplete picture of our reality.

Here’s the good news. The worldview I sketched may have been consistent with Newton’s model of classical physics, but it certainly misses the richness of science in terms of where it is today and where it’s going. Specifically, in solving some of the mysteries currently at hand, science can offer an expanded (but still naturalistic) worldview which both improves its explanatory power and also closes the gap with some of our intuitions about reality. In turn, this will lead to greater cultural consensus.

While I can’t know in detail how things will develop, here is a list of some current issues facing science, the resolution of which I believe should lead toward an improved and more unifying worldview. It would be great if any readers could add to this list.

1. Unifying quantum mechanics with the rest of science. As is well known, the mechanistic worldview breaks down when scientists analyze the subatomic domain. Quantum mechanics implies probabilistic causality, wave/particle duality, and non-local interaction. So far there has been a disjunction between quantum physics and the rest of science which has prevented these features of the theory from penetrating into the cultural perception of the scientific take on reality. As physicists make progress toward integrating quantum mechanics into a theory which also describes the macroscopic and cosmological scales, it seems reasonable to expect some of the implications of quantum theory to become a foundational aspect of all of science. In turn, this may help explain some phenomena which are hard to understand through a reductionist, mechanistic analysis.

2. Improving upon the original Big Bang theory. When most of us first heard of the Big Bang it was described as follows: the universe, including the dimensions of space and time themselves, originated in an infinitely dense, infinitely small point (a singularity), which expanded to form our universe. This idea of an emergence from a singularity seemed to have little to recommend it over non-scientific conceptions of creation. Now, if one reads the literature further, you find that this conception of a singularity is apparently ruled out by quantum physics. It seems as likely that our observable universe arose from some pre-existing reality. Some physicists now postulate that we could be part of a “multi-verse”. An improved theory of origin will aid the development of an even more compelling worldview.

3. Accounting for the one directional “arrow of time” in physics. Our experience of the flow of time is not captured well by current physical theories, most of which are time-symmetric. While the second law of thermodynamics has time-directionality, it is not incorporated into more fundamental physics or to a theory of cosmological origin. If scientists can uncover evidence for the flow of time as a necessary outgrowth of more fundamental laws, that would be a meaningful advance.

4. Integrating “complexity theory” more completely into the rest of science. As a layperson, I have been exposed to the concepts of “dynamical non-linear systems”, “dissipative systems”, “chaos” theory, “self-organizing systems”, etc. It seems that science has improved its toolkit for understanding natural systems which exhibit some remarkable phenomena. For example, simple algorithms can yield complicated, yet ordered outcomes. Higher order features of a system can emerge which could not be predicted from a reductive analysis of component parts (the parts seem to “know” what role they should play in the larger system). Jumbled pieces can appear to spontaneously assemble into a new organization. While I know part of the problem is my own limited knowledge of this topic, it seems as if this type of systems analysis is not integrated into more fundamental theories of physics. If it could be, it would foster the development of a richer cultural conception of the scientific worldview.

5. Incorporating first-person experience into the scientific worldview. (A “big one”, in my view). Science proceeds by adopting an objective, or third-person, stance toward natural phenomena. One simulates objectivity by carefully examining data using methods which lead to repeatable results which can be validated by others. The one empirical fact which cannot be analyzed in this way is first-person experience itself. As I have commented on at greater length before, a modification of the scientific worldview will be required to include subjective experience as a fundamental feature of reality. This will lead to an expanded but still naturalistic perspective which offers a more fitting home for humanity.

Tuesday, July 13, 2004

The first two definitions of “feelings” in my dictionary are 1. The sensation involving perception by touch and 2. An affective state of consciousness, such as that resulting from emotions, sentiments, or desires.

Considering these two definitions of feelings prompts these thoughts about human consciousness and its relation to the rest of the natural world.

1. Vision is the dominant sense of modern humans. The largest part of the sensory processing portion of the brain is devoted to sight, and this part of the brain has been the most studied. And it seems that when philosophers throughout history have tried to develop their models of how humans interact with the world and gain knowledge, they usually have vision at the forefront of their thinking.

An emphasis on vision biases one toward a passive conception of the human mind. We are seen as a vessel waiting to be stimulated by the influx of data from the world. The problem then becomes, how do we then process that data? How does that input get translated into output by cognitive processing? This way of approaching the study of human consciousness and brain functioning has been dominant.

All of our attributes arose through evolution. The prototypes and predecessors to our human-style consciousness can be found in our evolutionary past. However, in terms of evolution, it is the sense of touch which is primordial.

While lacking our nervous system, it seems clear that early organisms knew the world by touching it. They sensed opportunities for food, they felt out where the warmth of the sun was stronger, they sensed the possibility of danger. Touch is an active sense. One reaches out to the world: by touching you change the world and you change yourself.

I think progress in understanding human consciousness benefits from taking on the perspective given by this primordial sense of touch. This is the view of humans as active agents in the world, co-evolving with our environment. Contemplative, reflective, passive self-consciousness is newer on the evolutionary scene and while this mode is a crucial part of who we are, it obscures our more fundamental nature.

2. A few years ago, I read a book which put forth a model of how human consciousness worked. When I got to the end, I realized the author had never mentioned emotions. Feelings, emotions, affect -- these are integrated throughout human consciousness. The idea that the “higher” analytic cognitive functions are completely separate from emotions is a misconception. More recent accounts of the human mind, such as those found in the books of neuroscientist Antonio Damasio, show that emotion cannot be separated without degrading other cognitive functions.

Emotions are indeed markers of our evolutionary past as well as a crucial part of our present. We say that animals have instincts rather than higher thought processes. Many would deny that animals have any consciousness as we think of it in humans. Well, I am confident animals experience feelings as they interact with their environment. As we go down the scale to simpler or more primitive organisms, presumably feelings get simpler and more primitive.

And here the two definitions of feelings appear to me to converge. When the first primitive organisms felt their environment, they experienced a feeling.

Human subjective experience, at its core, is a complex of feelings which arise through our interaction with the world.

Thursday, July 08, 2004

Everyone anticipates continued progress in producing faster and faster computers which are capable of ever more amazing feats. A couple of years ago, a computer defeated a chess grandmaster. Researchers in artificial intelligence (AI) have been working on models of important features such as memory, sense perception, and language skills, and some have even attempted to bring these together in robots which can interact with their environment. In assessing these efforts, some believe that there is no reason to doubt that they will someday result in a machine which matches or exceeds overall human intelligence. Others doubt this is possible. Interwoven into this debate is the question of whether any such machine could be conscious? Again, some would answer yes, while others believe there would always be something essential to human consciousness which (in principle) could not be fabricated.

In addressing these questions, I need to say what I mean by intelligence and consciousness.

I want to follow the common practice of defining ultimate success in artificial intelligence as the creation of capabilities equivalent to human intelligence. Success in some narrow domain, such as chess-playing for instance, would not be sufficient to show human-style intelligence (evidently the chess computer succeeded through rapid “brute-force” computation, which is something at which we already know computers excel). But what criteria would satisfy a requirement for breadth as well as depth in intelligence? How would an AI researcher know if he or she succeeded in this task? Well, many have argued along the lines of “if it looks, walks, and quacks like a duck, then it’s a duck”. Alan Turing, the great English mathematician and pioneer of computer science advanced what became known as the Turing test for machine intelligence. In abbreviated form, the Turing test says that if a human being and a computer were questioned by a moderator (who didn’t know which was which) using text messages, and if the moderator could not distinguish them by their responses to his or her questions, then the machine would qualify as intelligent. For present purposes, I take the Turing test to be a reasonable way to define success in AI. (I should note that Turing actually defined the problem in terms of the question “Can machines think?”)

What about artificial consciousness (AC)? In defining consciousness, I am using consciousness in its sense as phenomenal awareness – the qualitative subjective experience of being. To bring this issue into focus, consider the following question: if we built an entity which could pass the Turing test, would its subjective experience be like ours? Would it have an “inner-life” at all? Some philosophers and scientists (including I believe Turing) would reject these questions as meaningless. After all, I can’t be sure that other people have the same sort of subjective experience as I have! However, despite the level of difficulty, I think it is a real and important question. I believe first-person subjective experience is a crucial part of our natural world and accounting for its presence and manifestation in the world is an appropriate (and extremely important!) challenge for science and philosophy.

Let me give my conclusions, and then try to back them up. First, I believe that success in creating a human-like artificial intelligence is possible in principle. This is because I believe that human intelligence is a natural phenomenon, and there is no need to invoke transcendent or supernatural explanations to account for it. If we can arise in the world, then other intelligent entities can come forth as well. We don’t need any extra “stuff”.

Also, because I have concluded that the raw material of subjective experience must be a ubiquitous part of the natural world, I don’t have a reason to assert that an artificial being couldn’t be conscious. In fact, I believe that if we could succeed in building an artificial intelligence, we would simultaneously create a robustly conscious being. We would not create a robot or zombie which somehow lacks any inner experience.

However, I believe that success in creating an intelligent and conscious artificial entity in the foreseeable future will be very, very difficult as a practical matter; and, specifically I predict that the digital computer, which is currently the vehicle for AI work, will likely not be the platform for a successful creation.

Human intelligence and consciousness is the product of a multi-billion year evolutionary process. Here, I refer to evolution in the broadest sense: this includes the physical evolution of the universe prior to the first life-forms, the more-familiar story of biological evolution on earth, as well as the much more recent explosion of cultural evolution.

The elementary building-blocks of human intelligence and consciousness were in place in the early universe. The idea that some prototype of consciousness, in particular, exists in the basic components of the universe is a strange and new concept for most people, so let me summarize the idea. As I have argued at greater length elsewhere, the conclusion that a kind of subjective experience is part of the substance of the universe follows from two simple assertions. First, subjective (first-person) experience is an irrefutable fact of existence which cannot be explained away by reducing it via traditionally third-person or “objective” scientific analysis, the way water is described by breaking it down into H2O. Second, subjective experience could not have just popped into existence out of nowhere at some point in biological development. The foundation for it had to be there already.

So, human consciousness in its current form is the product of evolutionary development of increasingly complex new forms of organization. The reason rocks differ from human beings lies in the way they are put together, not in their elementary constituents. The good news in this for AC ambitions is that we do not need to find some magic ingredient in order to create consciousness. The bad news is that the system which gives rise to human consciousness is so extremely intricate: we are the most complex entities known in the universe by far. In particular, I believe there is something very special about the way all biological entities “leverage” the proto-conscious experience of their primitive parts up through the levels of organic molecule, cell and organism. Then on top of this we humans add the unique complexity of our brain and nervous system. There is a great deal going on at each level of structure. For example, our cells have a particularly complex make-up. They are active entities in their own right with significant internal structure.

As an aside, the complexity of cells means that neurons specifically are much more than digital bits. This means attempts in AI research to model the brains’ neuron network on a computer will still be greatly oversimplifying the organization underlying human experience.

Let’s leave the question of human consciousness briefly and return to the question of intelligence. We are perhaps more used to the idea that the set of capabilities we call intelligence arose through evolution (the ability to speak and reason, for instance). While the details are debated, the idea that intelligence developed through natural selection is widely accepted. What perhaps is sometimes under- appreciated is the implication that intelligence arose as a method of enhancing survival, rather than popping into the world as an all-purpose analytical engine (like a computer). The broader point I wish to make is that we human beings are intrinsically active, not passive. Our intelligence does not exist in isolation inside our heads, waiting to analyze inputs. We are active agents constantly interfacing with our physical and social/cultural environment, and this environment is therefore also part of the foundation of our being. For AI to fully succeed, an artificial construct will also need to be an independent active entity which can match its internal capabilities with the dynamism of the external world.

Now to tie back intelligence to consciousness: I believe action in the world is always accompanied by some kind of experience. Consider the alternative for a moment. Some philosophers, grappling with the mysteries of consciousness, speculate that there could be an intelligent entity which not actually conscious: it would go about its business, acting like a fully intelligent being with appropriate behavior, without any kind of inner subjective experience (human consciousness in this view is epiphenomenal: it accompanies our actions, but does not play any necessary role). Science fiction has sometimes dealt with scenarios involving intelligent robots: are they persons in the same way we humans are? Do they have feelings, etc? In my view, higher levels of (active) intelligence co-arose with more robust experience through evolution. This implies human-level intelligence and consciousness couldn’t exist without each other. I think the idea that intelligence could exist without consciousness is fostered by our seeing the hints of intelligence in today’s computers. But if I’m right, these hints are still a far cry from the actual AI success: a fully independent, interactive and dynamic intelligent artificial agent. Such a being would necessarily be conscious.

To conclude, I think AI and AC are possible in principle. Our human capabilities are natural in origin, and every step in our understanding of nature will also bring forward our understanding of intelligence and consciousness. On the other hand, because human capabilities arise from such great complexity, we still have a long way to go on this journey. My speculation is that a significant advance, such as quantum computing or a biologically-based computing foundation, will be necessary to move toward success.

Friday, July 02, 2004

I certainly recommend this book to any layperson that enjoys reading accounts of both the history of physics and the state of progress in modern physics. Greene is an excellent writer and he discusses and teaches often difficult concepts in an accessible way. On reflection, my only criticism of the book is really an issue with the subject of string theory, rather than with Greene’s descriptions.

For me, the book breaks down into two parts. The first 2/3 is an account of historical developments in physics using an excellent organizing scheme. Greene sets out two key questions. First, are space and time fundamental or do they simply arise as descriptions of relations among other fundamental entities? Second, how do we account for the unidirectional flow of time (“the arrow of time”) which we experience?

With these questions in mind, Greene reviews classical physics, Einstein’s relativity, quantum mechanics, and recent cosmological theories.In Newton’s classical mechanics, space and time are fixed and absolute backdrops for matter and motion. (Leibniz was a contemporary that advocated the “relational” view that space and time emerged from relations between objects -- a view expressed in the late 19th century by Mach.) Einstein overthrew Newton with his special and general theories of relativity, where space and time are not independent and absolute, but are dynamically integrated with each other and with matter/energy. Greene explains carefully how Einstein’s framework was not fully relational, however. In quantum mechanics (the scientific method which accurately explains the behavior of sub-atomic entities), there is no absolute location in space, and the notions of space and time as usually conceived are bypassed by the phenomenon of entangled particles which instantaneously act on each other at a distance.

The best part of this first section of the book for me was the review of cosmological theories, particularly the inflationary hypothesis. After describing the second law of thermodynamics (the only part of traditional science which has an explicit arrow of time), Greene examines theories of the history of our universe for a possible explanation of both the flow of time we experience as well as the geometry of observed space. I understood the attraction of the inflationary scenario much better after reading the book.

The second part of the book is a discussion of progress in the attempt to reconcile relativity and quantum mechanics in a unified framework. Most of the discussion is on string theory (and its development into M-theory), which is both Greene’s specialty as well as the major (but not only) unification theory being developed.

String theory’s major exciting starting point was its promise to explain all of the fundamental particles and forces (including gravity) in a framework of one-dimensional units called strings. To laypeople, it is usually put forth that different vibrations in the strings describe all of the fundamental entities. (For me, it has always seemed like a good idea to try to create a model which replaces the dimensionless mathematical point of traditional physical theory with a basic unit which has more structure.) However, the working out of string theory was accompanied by difficulties. First, there were several versions, not just one. More importantly (in terms of the nature of space and time), in its initial formulations string theory required an absolute backdrop of space-time, thus in a way reverting to a pre-relativity stance. Also, to work, there had to exist many more dimensions of space – a total of ten space-time dimensions. (I should note that, to his credit, Greene does a good job throughout presenting criticisms and possible shortcomings of string theory.)

In recent years, Greene tells us, it was discovered that several different versions of string theory really were one theory after all. This overarching theory (which now featured an eleventh space-time dimension) also introduced new structures beyond one-dimensional strings. These 2, 3 and higher dimensional entities became known as branes, and the theory as M-theory (“M” possibly standing for membrane, but maybe several other things as well). Given that the mathematics in which the theory is described is so far beyond the typical reader, Greene describes the theory effectively and defends it against the common criticism that its details are not provable – he outlines experiments which could make key features testable in the not-too-distant future.

Greene finishes by trying to recover the concepts of space and time (as we know them) by postulating that they emerge from a more complex foundational reality described by M-theory. I should also note that in the book he discusses a number of interesting topics that are somewhat off the track of his core narrative, such as time-travel and wormholes, and the holographic principle. As always, the descriptions are interesting and reader-friendly.

Despite the fact that I doubt string theory can be described any better than Greene does it, the second part of the book is less compelling than the first. Part of the reason is simply the benefit of hindsight which enables the author to organize and present an effective narrative of the physics of the past, in contrast to describing the messier developments of a work-in-progress. However, in reflecting on Greene’s account, I think there’s more to it than that. I’m struck by the fact that many of the historical examples of progress in physics featured brilliant conceptual advances which built a framework for the resulting theory, while this is less clearly the case for M-theory. The paradigm case is general relativity, where Einstein had the insight that gravitation is equivalent to acceleration, and then he found a pre-existing mathematical framework in which to formulate the specifics of the theory. In contrast, my impression is that the small army of mathematically gifted M-theory modelers steer a course somewhat un-tethered to guiding concepts, and then attempt later to go back and fix things up. For example, Greene describes current attempts to draw connections to cosmological theories like inflation and to address conceptual shortcomings like space-time background-dependency.

It may be that a new key conceptual insight will be needed to guide the advance of modern physics.

Thursday, July 01, 2004

Freud outlined a grand scheme of the human mind, and many of the details have been contradicted or superseded by subsequent research in psychology and neuroscience. But one big piece of the puzzle he got right was that a large amount of processing goes on unconsciously. We have access to some of the operations of our brain and body through our thoughts and feelings, but many functions go on without conscious access. These include the more obvious examples of basic bodily functions (digestion, hormone release, etc.), but also some higher cognitive processes, such as laying down and organizing memories. Most of us have even had the experience of having unconsciously worked out a complex problem while our attention was directed elsewhere.

In my earlier posts, I asserted that a key to a better understanding of the universe was to realize that consciousness was a fundamental, irreducible part of nature, and also that it was everywhere in the universe. Given this, what in the world is the unconscious?!

I raise this issue in order to refocus on this potentially difficult part of my earlier discussion. I said (in my June 2004 post entitled “Evolution and the Ubiquity of Consciousness”) that while human capabilities are unique in the known world, some sort of basic or primitive consciousness must exist even in the world’s most fundamental and simple parts. Our quality of being an experiencing subject could not have suddenly appeared out of nowhere in the course of evolution.

Using the word consciousness to describe this ubiquitous feature of the world can be misleading. On the one hand I like that it conveys dramatically how my worldview differs from the conventional scientific stance: we exist as part of an evolving conscious universe as opposed to a world defined as consisting of inanimate matter/energy. On the other hand, simple organisms and of course inorganic parts of the world do not have anything which approaches human consciousness, so I am stretching the word to its limits when I use it in this way.

Like some philosophers who have followed this line of thinking, I have concluded that utilizing the word experience rather than consciousness (or mind) can clarify the argument. In fulfilling its role in the evolution of the universe, then, each part or system inherently has some level of subjective experience. The qualities or robustness of this experience, of course, varies widely and depends on the complexity of the system.

With this in mind, let me return to the topic of the “unconscious”. Given my arguments, the functioning of our brain and body in its unconscious mode is not without some level of experience, which is inherent in components such as our cells (or cell groupings). However, this is a primitive sort of localized experience which simply withers in comparison with the full-blown holistic and reflective experience of the healthy conscious human.

Why is there an unconscious mode at all? Part of the reason is that some of our lower-level processes are holdovers from more primitive stages of evolution and naturally are unaccompanied by the high-level human-style experience. In the case of unconscious processing which seems to be of a higher-order, the explanation is not as clear, but there is evidence that natural selection has deliberately constrained the scope of full human reflective consciousness so that we are not overwhelmed by input. Psychological studies have shown that humans don’t function well if faced with too much (or too little) stimulation.

One last issue for this post: how does this primitive experience of cells or other component parts of a human being get transformed into the full human version of consciousness? While the details are sketchy at present, I believe the evolution of higher and higher levels of complex functioning has been naturally accompanied by an increasingly robust leveraging of the experiential quality inherent in the world. This has reached its pinnacle in us: the highest cognitive abilities of the human brain have been attained hand-in-hand with the richness of the human conscious experience.